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Commit fb1013a0 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Rafael J. Wysocki
Browse files

intel_idle: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke the
callbacks on the already online CPUs.

The two smp_call_function_single() invocations in intel_idle_cpu_init() have
been removed because intel_idle_cpu_init() is now invoked via the hotplug
callback which runs on the target CPU. The IRQ-off calling convention for
auto_demotion_disable() and c1e_promotion_disable() has not been preserved
because only those two modify the MSR during CPU intialization.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 29d7bbad

drivers/idle/intel_idle.c

+39 −64
Original line number Diff line number Diff line
@@ -98,8 +98,6 @@ static int intel_idle(struct cpuidle_device *dev, 
			struct cpuidle_driver *drv, int index);

static void intel_idle_freeze(struct cpuidle_device *dev,

			      struct cpuidle_driver *drv, int index);

static int intel_idle_cpu_init(int cpu);



static struct cpuidle_state *cpuidle_state_table;



/*
@@ -951,50 +949,15 @@ static void intel_idle_freeze(struct cpuidle_device *dev, 
	mwait_idle_with_hints(eax, ecx);

}



static void __setup_broadcast_timer(void *arg)

static void __setup_broadcast_timer(bool on)

{

	unsigned long on = (unsigned long)arg;



	if (on)

		tick_broadcast_enable();

	else

		tick_broadcast_disable();

}



static int cpu_hotplug_notify(struct notifier_block *n,

			      unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;

	struct cpuidle_device *dev;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_ONLINE:



		if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)

			__setup_broadcast_timer((void *)true);



		/*

		 * Some systems can hotplug a cpu at runtime after

		 * the kernel has booted, we have to initialize the

		 * driver in this case

		 */

		dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);

		if (dev->registered)

			break;



		if (intel_idle_cpu_init(hotcpu))

			return NOTIFY_BAD;



		break;

	}

	return NOTIFY_OK;

}



static struct notifier_block cpu_hotplug_notifier = {

	.notifier_call = cpu_hotplug_notify,

};



static void auto_demotion_disable(void *dummy)

static void auto_demotion_disable(void)

{

	unsigned long long msr_bits;
@@ -1002,7 +965,7 @@ static void auto_demotion_disable(void *dummy) 
	msr_bits &= ~(icpu->auto_demotion_disable_flags);

	wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);

}

static void c1e_promotion_disable(void *dummy)

static void c1e_promotion_disable(void)

{

	unsigned long long msr_bits;
@@ -1422,12 +1385,11 @@ static void __init intel_idle_cpuidle_driver_init(void) 
 * allocate, initialize, register cpuidle_devices

 * @cpu: cpu/core to initialize

 */

static int intel_idle_cpu_init(int cpu)

static int intel_idle_cpu_init(unsigned int cpu)

{

	struct cpuidle_device *dev;



	dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);



	dev->cpu = cpu;



	if (cpuidle_register_device(dev)) {
@@ -1436,17 +1398,36 @@ static int intel_idle_cpu_init(int cpu) 
	}



	if (icpu->auto_demotion_disable_flags)

		smp_call_function_single(cpu, auto_demotion_disable, NULL, 1);

		auto_demotion_disable();



	if (icpu->disable_promotion_to_c1e)

		smp_call_function_single(cpu, c1e_promotion_disable, NULL, 1);

		c1e_promotion_disable();



	return 0;

}



static int intel_idle_cpu_online(unsigned int cpu)

{

	struct cpuidle_device *dev;



	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)

		__setup_broadcast_timer(true);



	/*

	 * Some systems can hotplug a cpu at runtime after

	 * the kernel has booted, we have to initialize the

	 * driver in this case

	 */

	dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);

	if (!dev->registered)

		return intel_idle_cpu_init(cpu);



	return 0;

}



static int __init intel_idle_init(void)

{

	int retval, i;

	int retval;



	/* Do not load intel_idle at all for now if idle= is passed */

	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
@@ -1466,35 +1447,29 @@ static int __init intel_idle_init(void) 
		struct cpuidle_driver *drv = cpuidle_get_driver();

		printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",

			drv ? drv->name : "none");

		free_percpu(intel_idle_cpuidle_devices);

		return retval;

	}



	cpu_notifier_register_begin();



	for_each_online_cpu(i) {

		retval = intel_idle_cpu_init(i);

		if (retval) {

			intel_idle_cpuidle_devices_uninit();

			cpu_notifier_register_done();

			cpuidle_unregister_driver(&intel_idle_driver);

			free_percpu(intel_idle_cpuidle_devices);

			return retval;

		}

		goto init_driver_fail;

	}

	__register_cpu_notifier(&cpu_hotplug_notifier);



	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */

		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;

	else

		on_each_cpu(__setup_broadcast_timer, (void *)true, 1);



	cpu_notifier_register_done();

	retval = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "idle/intel:online",

				   intel_idle_cpu_online, NULL);

	if (retval < 0)

		goto hp_setup_fail;



	pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",

		lapic_timer_reliable_states);



	return 0;



hp_setup_fail:

	intel_idle_cpuidle_devices_uninit();

	cpuidle_unregister_driver(&intel_idle_driver);

init_driver_fail:

	free_percpu(intel_idle_cpuidle_devices);

	return retval;



}

device_initcall(intel_idle_init);